Method for increasing pill resistance and density of blended staple polyethylene terephthalate and cellulosic fabrics by applying specific chemical shrinking agents for the polyethylene terephthalate



2,897,042 Patented July 28, 1959 METHOD FOR INCREASING PILL RESISTANCE AND DENSITY OF BLENDED STAPLE POLY- ETHYLENE TEREPH'IHAL ATE AND ELLU-.

IJOSIC FABRICSBY APPLYINGSPECIEIC CHEM- ICAL SHR'INKING AGENTS FOR THE POLY- TEREPHTHALATE John R. Heiks, Wilmington, Del., as'signor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Application June 30, 1955 Serial No. 519,230

4 Claims. c1. s- -130.1

This invention relates to a finishing treatment. for blended fabrics containing substantial. amounts of polyester fibers. More particularly, it relates to a process for increasing the Weight per unit areaof such fabrics.

Fabrics containing a high percentage of the polyester fibers of Whinfield Patent No. 2,465,319, and particularly polyethylene terephthalate, resemble 100% woolen fabrics more closely than do fabrics containing other commercial synthetic fibers. This fact, together with the excellent shape retention and lightness inv weight possessed by the fabrics containing polyester fibers, has led to substantial commercial acceptance of such fabrics.

Because of the improved properties of fabrics containing polyester fibers, there has been a demand for such fabrics containing increased percentages of the polyester fibers. Heretofore, fabrics containing high percentages of polyester fibers have not been completely acceptable. Perhaps the most outstanding problem in connection with the fabrics containing high percentages of the polyester fibers is the tendency for such fabrics to form pills on the surface of the fabric. The increased tendency towards pill formation in these high polyester fiber fabrics apparently is caused by excessive polyester fibers on the surface of the fabric that become entangled into pills.

Not only has there been a'need for high polyester fiber fabrics with increased pill resistance, but also there has been a need for high polyester fiber fabrics of increased density wherein the polyester fibers are concentrated internally of the fabric. Such a fabric inherently will have high pill resistance as well as numerous other characteristics that make it ideal for many uses.

It is an object of this invention to produce high density fabrics containing substantial amounts of polyester fibers in conjunction with other fibers. It is a further object to produce such a fabric wherein the polyester fibers are concentrated internally of the fabric.

These objects are accomplished by selecting a fabric containing from 25-95% of polymeric polymethylene terephthalate fibers and shrinking the polymeric pol'ymethylene terephthalate fibers an average of at least 18% of their initial lengths.

The shrinking step is accomplished in accordance with this invention by treating the fabric for at least two minutes with an aqueous liquor containing a certain type of shrinking agent. During the shrinking of the fibers the fabric is substantially free of tension. The liquor is maintained at a temperature from about 160 F. to its boiling temperature, ordinarily about 212 F., and preferably at about its boiling temperature.

The shrinking agents of my invention are phenol and phenols substituted in any position with hydrocarbon groups containing from 1-6 carbon atoms. Thus the shrinking agents employed can be orthoor para-cresol, paraor meta-phenylphenol, ortho-, paraor meta-ethylphenol or the various xylenols.

While the phenols listed abovegive relatively high shrinkage of the fabrics under optimum conditions, by far the best shrinking agents, and by no means equivalents of those listed above, are meta-cresol andortho-phenyh phenol. These preferred shrinking agents give consistently excellent performance, producing the desired high density fabrics of outstanding quality.

In the shrinking treatment, the polyester fibers are shrunk substantially more than the other fibers present in the fabric. Consequently, the other fibers tend to loop 7 and bunch. up into the surface of the fabric While the polyester fibers become straightened out and concentrated internally of the fabric thereby being less available for pill formation.

As will be observed from the following examples, during the shrinking treatment the fabric shrinks substantially more warp wise than it does fill-wise. It has been found that to produce a satisfactory fabric in accordance with this invention it is necessary that the fabric shrink at least 22% warp-wise, and preferably 25% or more, and at least 15% fill-wise, and preferably 18% or more, giv-' ing an overall average fabric shrinkage of at least about 18%. Obviously then the polyester fibers must shrink more than 18% of their initial lengths.

Using a shrinking liquor containing only meta-cresol as the shrinking agent, it has been found that the liquor must contain at least about 4% by weight of'meta-cresOl to give the required 18% average shrinkage. Alternatively the required amount of shrinking is obtained by treating the blended fabric with a liquor containing at least 1% of ortho phenylphenol. Likewise, it has been found that the requisite shrinkage is obtained using aqueous liquors containing mixtures of meta-cresol and ortho-phenylphenol provided that the sum of the weight percentage of the ortho-phenylphenol and M4 the weight percentage of the meta-cresol present in the liquor equals at least 1 percent.

Since no substantial increase in shrinkage is obtained by using a liquor containing in excess of about 7% of meta-cresol or about 4% ortho-phenylphenol, and since excessive amounts of these materials undesirably affect some fabrics, it is preferred to use liquors not in excessof these concentrations. Likewise when the treating liquor contains both these shrinking agents the percentage of ortho-phenylphenol plus A the percentage of metacresol preferably does not exceed 5.75%.

To illustrate the practice of the present invention the following examples are given:

Example 1 A plain weave tropical greige fabric made from a blend of '45 wool and 55% 3-denier polyethylene terephthalate staple fiber having a staple length of 2.5 inches wasv placed into a tumble washer containing a 5% by weight aqueous solution of rn-cresol at a temperature of 200 F. The fabric was thusly Washed with agitation in the tumble washer for 15 minutes.

After removal of the fabric from the tumble washer it was scoured in a 1% solution of ether-alcohol sulfate at 200 F. for 15 minutes and subsequently rinsed with water to remove m-cresol. I

It was found that the fabric had shrunk 28% warp-wise and 20% fill-wise during this treatment. The fabric weight had increased from 4.8 oz./ sq. yd. to 8.1 oz./sq. yd. with an increase in thickness from 0.019 inches to 0.024 inches.

Numerous pieces of this treated tropical greige fabric were dyed successfully and finished by conventional procedures. The fabric had excellent liveliness, compressional resilience, wrinkle resistance, crease-recovery, elasticity and a greatly increased resistance to pilling.

Example 2 A fabric made from 85% of polyethylene terephthalate staple fiber and 15% cellulose acetate staple fiber, both of a staple length of 2.5 inches, was treated in accordance 1 Example 3 Three two-yard samples of the fabric of Example 1 were treated in a tumble washer in accordance with the procedure of Example 1 but at varying m-cresol concentrations. scour at the boil with a 0.1% solution of an ether-alcohol sulfate with agitation. The following table shows the effect of these treatments. Under the heading Shrink- This treatment was followed by a -minute age, W stands for warp-wise and F stands for fill-wise.

Concentration of m-creso Fabric shrinkage Thickness,

inches Example Three twoyard samples of the blended fabric of EX- ample 1 were treated in a tumble washer in accordance with the procedure of Example 1 but at varying liquor temperatures. Following this treatment the samples were scoured in accordance with the procedure of Example 3. The following table shows the effect of this treatment:

Temperature Fabric shrinkage 60 F 11% W 5% F. 160 F 23% W 15% F. 212 F 28% W 18% F.

Results similar to those of Examples 1 thru 3 are obtainable by including o-phenylphenol in the treating liquor provided that the numerical sum of the weight percentage of the o-phenylphenol plus A the weight percentage of m-cresol present in the liquor falls Within the range of 1 to 5.75%.

Example 5 Three samples of the polyester fiber-wool fabric of Example 1 were treated in a tumble washer in accordance with the procedure of Example 1 except that the shrink liquor contained varying amounts of o-phenylphenol in place of the m-cresol of Example 1. This treatment was followed by a scour with an ether-alcohol sulfate solution to remove the treating liquorfrom the fabrics. The following table shows the eifect of these treatments:

Concentration of o-phenylphenol Fabric shrinkage 1.0%- 22% w 17% F 2.0%; 25% W 22% F 3.07 25% 22% F The process of this invention is applicable to all fabrics containing substantial amounts of polyester fibers in conjunction with other fibers, whether the fabric be woven, felted or otherwise fabricated. For example, this process is applicable to fabrics containing, besides polyester fibers, natural fibers such as wool, cotton, linen and the like, and synthetic fibers such as polyacrylom'trile fibers, polyamide fibers, and the various rayon fibers. Of course, the fabric should not contain fibers that are substantially damaged by the shrinking agents.

The process can be applied at any stage in the conventional treatment of the fabric. If desired, the shrink treatment can be carried on simultaneously with the dyeing of the fabric. Preferably it is carried on prior to dyeing of the fabric since the treatment of dyed fabric in many instances causes bleeding off of dye.

I claim:

1. A method for increasing the pill resistance and density of a fabric made from a blend of staple textile fibers and containing from 25% to by Weight, of polyethylene terephthalate staple fibers and from 5% to 75%, by weight, of a non-pilling cellulosic fiber, comprising the step of shrinking the polyethylene terephthalate fibers an average of at least 18% of their lengths so that the nonpilling staple fibers in the fabric, which shrink less than the polyethylene terephthalate fibers, bunch up into the surface of the'fabric by treating said'fabric for at least two minutes with an aqueous liquor containing from 0-4% by weight of ortho-phenylphenol and from 07% by weight of meta-cresol, with the sum of the percentage of the ortho-phenylphenol and A the percentage of meta cresol in the liquor equaling from 1 to 5.75%, said liquor being at a temperature of from about F. to its boiling temperature.

2. The method in accordance with claim 1 wherein the aqueous liquor contains from 47% by weight of metacresol.

3. The method in accordance with claim 1 wherein the aqueous liquor contains from 1-4% by weight of ortho-phenylphenol.

4. The method in accordance with claim 1 wherein the aqueous liquor is at its boiling temperature.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Du Pont Dacron Tech. Manual, sec. 2, page 3.03, July 21, 1952. 

1. A METHOD FOR INCREASING THE PILL RESISTANCE AND DENSITY OF A FABRIC MADE FROM A BLEND OF STAPLE TEXITLE FIBERS AND CONTAINING FROM 25% TO 95%, BY WEIGHT, OF POLY ETHYLENE TEREPHTHALATE STAPLE FIBERS AND FROM 5% TO 75%, BY WEIGHT, OF A NON-PILLING CELLULOSIC FIBER, COMPRISING THE STEP OF SHRINKING THE POLYETHYLENE TEREPHTHALATE FIBERS AN AVERAGE OF AT LEAST 18% OF THEIR LENGTHS SO THAT THE NONPILLING STAPLE FIBERS IN THE FABRIC, WHICH SHRINK LESS THAN THE POLYETHYLENE TEREPHTHALATE FIBERS, BUNCH UP INTO THE SURFACE OF THE FABRIC BY TREATING SAID FABRIC FOR AT LEAST TWO MINUTES WITH AN AQUEOUS LIQUOR CONTAINING FROM 0-4% BY WEIGHT OF ORTHO-PHENYLPHENOL AND FROM 0-7% BY WEIGHT OF META-CRESOL, WITH THE SUM OF THE PERCENTAGE OF THE ORTHO-PHENYLPHENOL AND 1/4 THE PERCENTAGE OF METACRESOL IN THE LIQUOR EQUALING FROM 1 TO 5.75%, SAID LIQUOR BEING AT A TEMPERATURE OF FROM ABOUT 160* F. TO ITS 